Oppenheim R W, Cole T, Prevette D
Department of Anatomy, Bowman Gray School of Medicine, Wake Forest University, Winston-Salem, North Carolina.
Dev Biol. 1989 Jun;133(2):468-74. doi: 10.1016/0012-1606(89)90050-x.
Regional differences in the number of motoneurons in the spinal cord of the chick are thought to arise developmentally by region-specific cell death and cell migration. In this way, a numerically homogeneous motor column throughout the spinal cord is believed to be molded into the adult pattern. Region-specific differences in proliferation are not thought to play a significant role in this process. By counting motoneurons in serial sections throughout the rostral-caudal extent of the spinal cord on Embryonic Day 4 in the chick, we have found that the numerical variations in motoneurons in different spinal cord regions are already foreshadowed by this stage, which is before the onset of both cell death and the secondary migration of neurons out of the motor column. These results indicate that although nonproliferative events may contribute to the later regional variations in motoneuron numbers, the initial differences themselves are created early on by regionally specific proliferative events.
鸡脊髓中运动神经元数量的区域差异被认为是在发育过程中由区域特异性细胞死亡和细胞迁移引起的。通过这种方式，整个脊髓中数量均匀的运动柱被认为会塑造成成年模式。增殖的区域特异性差异在这个过程中不被认为起重要作用。通过在鸡胚胎第4天对脊髓从头到尾的连续切片中的运动神经元进行计数，我们发现不同脊髓区域运动神经元的数量变化在这个阶段就已经有了预兆，而这个阶段是在细胞死亡和神经元从运动柱的二次迁移开始之前。这些结果表明，虽然非增殖性事件可能导致后来运动神经元数量的区域差异，但最初的差异本身是由区域特异性增殖事件早期产生的。
